Friday, December 12, 2014

Cormorants are in the Family Phalacrocoracidae, which contains over 40 species. Cormorants
are medium to large seabirds and tend to nest in colonies. They have mainly
dark plumage and many species have colored skin on the face that is more
pronounced during the breeding season.Their bills are long and thin, and they have webbing between all four
toes that helps propel them underwater. Cormorants often spread their
soaked wings out to dry after a dive due to incomplete waterproofing that helps
reduce buoyancy, a valuable attribute for this species of diving seabirds.

Haystack Rock is
host to three species of cormorants; the Pelagic
Cormorant (Phalacrocorax pelagicus), the Brandt’s Cormorant (Phalacrocorax
penicillatus) and the Double Crested Cormorant (Phalacrocorax
auritu). The Pelagic Cormorant is the species most commonly seen on the
rock.

Pelagic Cormorant (Phalacrocorax
pelagicus)

The Pelagic
Cormorant is one of the smaller of the species with a long body and a long,
slender neck. The bird’s slender bill
is blunt or hooked at its tip. The non-breeding adults have iridescent,
all-black plumage. Breeding birds have two short crests, one on the top of the
head and one on the nape. They also have a patch of dark skin below their eyes that
turn magenta during breeding season. They feed on fish and marine
invertebrates, diving and chasing their
prey under water. The
pelagic cormorant is among the least social of the cormorants, nesting in loose colonies or far from neighbors. This behavior leads them to
nest at the cliff face, usually on ledges. Their nests are built from grasses or
seaweed and is held together and adhered to the cliff by the birds’ guano. They
tend to return to the same nest site each year, repairing it as necessary each
season. They typically have a clutch of three or four eggs; the eggs are
typically greenish-white to blue. The Pelagic Cormorant is an abundant
and widespread species which can be
found in the open ocean during the winter.

Non-Breeding Pelagic Cormorant

Photo Courtesy of Susan Glarum

Breeding Pelagic Cormorant

Photo Courtesy of Susan Glarum

Brandt’s Cormorant (Phalacrocorax penicillatus)

The Brandt’s Cormorant is a one of the larger species of cormorants, and is found only in marine
environments. The bird has short black legs, a long body and neck, with a
medium-sized bill that is blunt or hooked at its tip. They have dark plumage
with a pale patch at the base of the dark colored bill. Early in the breeding
season, the bird has white plumes on its neck and back. Also in the breeding
season, adults have turquoise eyes and a bright blue gular pouch, which is very distinct from other cormorants. This blue color fades rapidly after the nesting season. The Brandt's cormorant feeds on small fish and
squid from the surface to sea floor, pursuing them by diving using its webbed
feet for propulsion. Like the pelagic cormorant, the Brandt's cormorant grabs its prey with its bill,
without spearing it.The
Brandt’s Cormorant, more social than the Pelagic Cormorant, often roosts and
nests in large groups. The bird makes a large nest on gentle slopes or steep
cliffs with ledges; the nests are built of grass, moss, weeds, and seaweed and
cemented together with the bird’s guano. Clutch size can range from three to
six eggs that are pale blue to bluish white. The Brandt's Cormorant is the
least vocal of the North American cormorants making sounds that are audible
only from a few feet away. In the
nonbreeding season the birds redistribute along the coast to locations where
food is available.

The Double Crested Cormorant is a large
cormorant and is the most numerous and widespread of cormorants in North
America. The bird has short dark legs with a long brownish-black to matte-black
body, a small head on a long, kinked neck, with bare orange skin around the
face and chin. The bill, about the length of the head, is lighter in color with
a strongly hooked tip. In the breeding
season a small plume on either side of the crown, of either black or white
feathers, is typically present. The adults will also have turquoise eyes and mouth
lining. Its diet is almost all fish, but may include insects,
crustaceans, and amphibians. The Double Crested Cormorant floats low on the water's surface and dives to
catch small prey. Their nests are built on cliff ledges and are mostly made of
finger-size sticks, but may include some seaweed and flotsam. Their nests are also typically
lined with grass. They are a social bird typically nesting in colonies, often
with other species of wading birds. The clutch size is typically three to four
blue eggs.